1. Field of the Invention
The present invention relates to an apparatus for automatically exchanging a number of record medium cassettes with respect to a recording and reproducing device or devices. Such an automatic cassette exchange apparatus may be advantageously used in a mass storage system of computer and broadcasting equipment. It should be noted that in the present specification, the record medium cassette means a cassette or cartridge of any shape and construction containing any kind of a record medium on and from which any kind of information can be recorded and reproduced.
2. Related Art Statement
A known automatic cassette exchange apparatus includes a cassette storing means for storing a number of record medium cassettes, a recording and reproducing means for recording and reproducing information on and from the record medium cassettes, a cassette transporting means for transporting the record medium cassettes between the cassette storing means and the recording and reproducing means, and a controlling means for controlling said cassette storing means, recording and reproducing means and cassette transporting means.
FIG. 1 is a schematic view showing a known apparatus for automatically exchanging record medium cassettes. The automatic cassette exchange apparatus includes a housing 1, in which a cassette storing unit 2 is arranged rotatably. In the housing 1, four recording and reproducing units 3 are provided above the cassette storing unit 2, and beside the cassette storing unit and the recording and reproducing unit, a cassette transporting unit 4 is arranged.
In the known automatic cassette exchange apparatus, when a cassette stored in the cassette storing unit 2 is to be set into the recording and reproducing unit 3, the cassette is first removed from the cassette storing unit 2 into a cassette hand over unit 5, and then the cassette hand over unit is moved by the cassette transporting unit 4 into a position of the recording and reproducing unit 3. Finally, the cassette hand over unit 5 inserts the relevant cassette into the recording and reproducing unit 3. When a cassette installed into the recording and reproducing unit 3 is to be returned into the cassette storing unit 2, the above mentioned operations are carried out in a reverse order.
FIGS. 2A-2D and FIGS. 3A-3B are schematic views showing the successive operation of the known automatic cassette exchanging apparatus.
When a cassette M1 installed in the recording and reproducing unit 3 is to be replaced by a cassette M2 stored in a cassette room 2A of the cassette storing unit 2, at first, the cassette M1 is inserted into the cassette hand over unit 5 as illustrated in FIG. 2A. Then, the cassette hand over unit 5 is moved by the cassette transporting unit not shown in FIG. 2 into a position in front of an empty cassette room 2B and the cassette M1 is inserted into the cassette room 2A as depicted in FIG. 2B. Next, the cassette hand over unit 5 is moved in front of the cassette room 2A and the cassette M2 stored therein is inserted into the cassette hand over unit 5 as illustrated in FIG. 2C. Then, the cassette hand over 5 is moved upward into a position in front of the recording and reproducing unit 3 and the cassette M2 is inserted into the recording and reproducing unit 3 as shown in FIG. 2D.
When cassettes M7, M8 - - - stored in lower cassette rooms 2G, 2H - - - have to be removed into upper empty cassette rooms 2A, 2B - - - , the cassette hand over unit 5 is first moved by the cassette transporting unit into a position in front of the cassette room 2G and the cassette M7 is inserted into the cassette hand over unit as shown in FIG. 3A. Then, the cassette hand over unit 5 is moved into a position in front of the cassette room 2A and the cassette is inserted into the cassette room 2A as illustrated in FIG. 3B. Next, the cassette hand over unit 5 is moved downward into a position in front of the cassette room 2H and the cassette M8 is inserted into the hand over unit. After that, the cassette hand over unit 5 is moved upward again into a position in front of the cassette room 2B and the cassette M8 is inserted into the cassette room 2B. The above mentioned operations are repeated to remove the cassettes within the cassette storing unit 2.
In the known automatic cassette exchange apparatus explained above, when one or more cassettes are required to be newly installed into the cassette storing unit 2 or one or more stored cassettes are required to be removed from the cassette storing unit 2, the following complicated operations have to be carried out.
(a) The operation of the apparatus is stopped and a door not shown is opened.
(b) Unnecessary cassette or cassettes are removed from the cassette storing unit 2 and one or more cassettes are newly installed in the cassette storing unit.
(c) The door is closed and the apparatus is operated again.
This operation is quite cumbersome and requires a rather long time, mainly due to a fact that the above explained operation could not be performed automatically.
Furthermore, in the known automatic cassette exchange apparatus, if the cassette hand over unit 5 becomes out of order, the whole apparatus could not operate correctly, and thus the cassette exchange and removal could not be performed any more.